/// <summary>
/// Gets a unicode string descriptor from the specified device.
/// </summary>
/// <param name="device">The device info of the device to get the descriptor from.</param>
/// <param name="stringIndex">The index of the string descriptor to get.</param>
/// <returns>True if USB transfer completed successfully. Otherwise, false.</returns>
public static UnicodeString GetUnicodeStringDescriptor(USBDeviceInfo device, byte stringIndex)
{
#if USB_TRACE
DBGMSG(((FOS_System.String)"USB: GET_DESCRIPTOR string, endpoint: 0 stringIndex: ") + stringIndex);
#endif
if (stringIndex == 0)
{
return new UnicodeString()
{
StringType = 0,
Value = "[NONE]"
};
}
UnicodeString result = new UnicodeString()
{
StringType = 0,
Value = "[Failed to load]"
};
//64 byte buffer
ushort bufferSize = 64;
StringDescriptorUnicode* buffer = (StringDescriptorUnicode*)FOS_System.Heap.AllocZeroed(bufferSize, "USBManager : GetUnicodeStringDescriptor");
try
{
USBTransfer transfer = new USBTransfer();
device.hc.SetupTransfer(device, transfer, USBTransferType.Control, 0, bufferSize);
device.hc.SETUPTransaction(transfer, 8, 0x80, 6, 3, stringIndex, 0x0409, bufferSize);
device.hc.INTransaction(transfer, false, buffer, bufferSize);
device.hc.OUTTransaction(transfer, true, null, 0);
device.hc.IssueTransfer(transfer);
if (transfer.success)
{
result = new UnicodeString()
{
StringType = buffer->descriptorType,
Value = buffer->length > 0 ? FOS_System.ByteConverter.GetASCIIStringFromUTF16((byte*)buffer->widechar, 0, buffer->length) : ""
};
#if USB_TRACE
ShowUnicodeString(result);
#endif
}
}
finally
{
FOS_System.Heap.Free(buffer);
}
return result;
}
private static void ShowUnicodeString(UnicodeString str)
{
DBGMSG(str.Value);
}